Question: Express this number in scientific notation. $0.002\;478$
Count the zeroes to the right of the decimal point before the leading $\leadingColor{2}$ : there are $2$ zeroes If you count the leading digit $\leadingColor{2}$ and those zeroes , there are $\exponentColor{3}$ digits to the right of the decimal point. So: $0.002\;478 = \leadingColor{2}.478 \times 10^{\exponentColor{-3}}$